title: Dependence of the product chain-length on detergents for long-chain E-polyprenyl diphosphate synthases.
abstract: Long-chain E-polyprenyl diphosphate synthases (E-PDS) catalyze repetitive addition of isopentenyl diphosphate (IPP) to the growing prenyl chain of an allylic diphosphate. The polyprenyl diphosphate products are required for the biosynthesis of ubiquinones and menaquinones required for electron transport during oxidative phosphorylation to generate ATP. In vitro, the long-chain PDSs require addition of phospholipids or detergents to the assay buffer to enhance product release and maintain efficient turnover. During preliminary assays of product chain-length with anionic, zwitterionic, and nonionic detergents, we discovered considerable variability. Examination of a series of nonionic PEG detergents with several long-chain E-PDSs from different organisms revealed that in vitro incubations with nonaethylene glycol monododecyl ether or Triton X-100 typically gave chain-lengths that corresponded to those of the isoprenoid moieties in respiratory quinones synthesized in vivo. In contrast, incubations in buffer with n-butanol, CHAPS, DMSO, n-octyl-β-glucopyranoside, or β-cyclodextrin or in buffer without detergent typically proceeded more slowly and gave a broad range of chain-lengths.
authors.affiliation: Department of Chemistry, University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112, United States.
authors.forename: Jian-Jung
authors.initials: JJ
authors.lastname: Pan
authors.forename: Gurusankar
authors.initials: G
authors.lastname: Ramamoorthy
authors.forename: C Dale
authors.initials: CD
authors.lastname: Poulter
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D002021:Buffers; D003902:Detergents / Q000737:chemistry*; D007700:Kinetics; D008025:Ligases / Q000737:chemistry*; D010085:Oxidative Phosphorylation; D010743:Phospholipids / Q000737:chemistry; D013379:Substrate Specificity
chemical_list: D002021:Buffers; D003902:Detergents; D010743:Phospholipids; D000255:Adenosine Triphosphate; D008025:Ligases